if you use telegram integration, you can try to send text with html links or attach a button with the desired link to the message
if you send manually, then in the text input box, press the right mouse button, select Formatting and there the item is add a link
This link is generated by LiqPay itself, it will not work to get a shorter version from the payment system, you can make a revision for this action to create a link, which will insert a shortened version of the link in the field, the link will be generated like this:
https://YOUR_URL/s4eWVK56W1this modification will cost 1 hour